Figure



Oct. 31, 1961 M. HEINEMANN ETAL 25,056-

PLUG-TYPE DOORS FOR PRESSURIZED CABINS Original Filed April 11, 1955 4Sheets-Sheet 2 A 7 rOEA/EVS M. HEINEMANN ETAL Re. 25,066

PLUG-TYPE D00Rs FOR PRESSURIZED cmams Oct. 31, 1961 4 Sheets-Sheet 4Original Filed April 11, 1955 Tmfl w m f L a2 6. m M

United States Patent Ofllicc Re. 25,066 Reissued Oct. 31, 1961 25,066PLUG-TYPE DOORS FOR PRESSURIZED CABENS Milton Heinemann and Varnell L.R. James, Seattle, Wash, assignors to Boeing Airplane Company, Seattle,Wasln, a corporation of Delaware Original No. 2,751,636, dated June 26,1956, Ser. No. 500,636, Apr. 11, 1955. Application for reissue Apr. 8,1957, Ser. No. 651,562

14 Claims. (Cl. 20-16) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in itaiics indicates the additions made by reissue.

This invention relates to closure devices and has its preferred or mostimportant application in aircraft pressure cabin doors. The invention isherein illustratively described by reference to the presently preferredform thereof as applied to an aircraft pressure cabin door; however itwill be recognized that certain modifications and changes therein withrespect to details may be made without departing from the essentialfeatures involved.

Two problems arise in conjunction with aircraft cabin doors, especiallywhen the cabin is pressurized, as are most cabins of present-daypassenger-carrying airplanes. One such problem has to do with the curvedformation of the aircraft and of the door, the necessity for maintainingthat curved conformation with virtually nointerruption to the smoothnessof the external contour while the aircraft is in flight, yet enablingthe opening outwardly of the door into a position preferably such thatit fits snugly against the cabins contour when the aircraft is at restupon the ground. The second has to do with the securing of the doorwhile in flight against bursting pressures arising from the elevatedcabin pressures, and especially without the necessity of sole relianceon securemcnt of the door by latches, locks and the like, which may failto be secured properly, which might be accidentally released while inflight, or which may fail mechanically.

There have been proposals for solving the first problem, and an instanceis found in the patent to Muller, No. 2,564,988. The Muller proposal,however, ignores the second problem, since the door seats inwardly fromthe exterior, and is held closed wholly by mechanical securing means.Should these fail, or become accidentally released during. flight, anoutdraft is created which, in some instances in the past, has swept anoccupant of the cabin outwardly through the suddenly opened doorway, andhe has fallen to his death.

There have been attempts also to solve the second problem, and anexample thereof is found in the copcnding application of F. W. M'cAfec,R, B. Snively, and A. A. Vannest, Serial No. 436,276, filed June 14,1954, now U.S. Patent No. 2,763,900, issued September 25, I956. TheMcAfec et a1. proposal includes a doorway, which is inwardly flangedalong the greater part of the sill and lintel, and one vertical side,leaving the fourth side and a portion of the sill and lintel' adjacentthe same unflanged, so that the door, which seats from the interioragainst the flanges and is held there by the superior cabin pressure,can, when the airplane is ground-borne, be moved edgewise through theunflanged portion of the doorway to the exterior, and so be folded backagainst the cabin structure at one side of the doorway. This proposal,however, is subject to the objection that the flanged portion of thesill, in particular, stands up above the general level of the sill, andunless means are taken to guard against the possibility, a passengerentering or leaving through the doorway may stumble on this projectingflange. The McAfee et al. proposal incorporates means to mask thisupstanding sill flange, but by so much adds to the weight, to the cost,and to the complexity of the structure.

According to the present invention, a door is employed which issufficiently larger than the doorway in lateral extent that it may seatfrom the interior outwardly against the two spaced jambs of the doorway.The door, however, is of a vertical extent just sufficiently less thanthe spacing between the sill and the lintel of the doorway that the doormay move edgcwisc through the doorway. Before it can so move, it must bedisplaced laterally and tilted on an upright axis so that it disengagesthe jambs and projects one of its side edges outwardly. Thereafter itmay be moved outwardly through the doorway, and finally laterally in aposition exteriorly of the cabin structure and alongside the doorway.When closed, because of the greater lateral extent of the door than ofthe doorway, the superior interior cabin pressure will act over theentire surface area of the door to hold the door seated against the morenarrowly spaced jambs, provision being made for sealing the upper andlower edges (indeed, for sealing all four edges) of the door. By thisconstruction the sill is free of any upstanding obstruction, the door isheld seated by the cabin pressure, and cannot possibly be opened whilein flight, yet when the aircraft is ground-borne and the internal andexternal pressures are equalized the door may readily be opened andmoved into an out-of-the-way exterior position, where its curved contourcorresponds generally to the similar contour of the adjacent aircraftcabin structure.

These ends are accomplished by supporting and guiding the door by meansof what may be termed an articulated double quadrangular linkagemechanism, in which one quadrangle has the function of displacing thedoor from its closed, seated position, slightly laterally and at thesame time tilting one of its edges inwardly and projecting the otheredge outwardly through the doorway, after which the second quadranglecomes into operation to function in the manner of approximately parallellinkage, to displace the door laterally while the first-mentionedquadrangle continues to project the door outwardly, or after suchprojection is completed. At the end of the movement the door is in itsopen position, alongside of the doorway and exteriorly of the cabinstructure. The linkage is so arranged as to move the door throughdefinite positions, so that it may not move uncontrollably under theinfluence of a propeller slip stream or other aerodynamic forces whichmay be acting upon the airplane, with the attendant possibility ofdamage to the door or to the cabin structure.

Viewed broadly, therefore, the invention provides a closure memberadapted when closed to seat against one side of the opening andmechanism supporting and guiding it to pass through the same to theopposite side thereof in order to move the closure member to openposition substantially clear of the opening. More specifically theinvention provides for controlling movement of the door, from closedposition, initially in the direction away from its seat, followed byswinging of the door to pass bodily generally edgewise in the oppositedirection through the doorway to open position clear of the doorway.

The objects of the present invention are understandable from the above,and the mechanism by which those objects are attained will be made clearin the following specification, aided by the accompanying drawings, bothof which disclose the invention in a typical embodiment, and the novelfeatures of the invention will be made clear by the appended claims.

FIGURE 1 is an interior elcvational view of the door in its closedposition, with parts of the operating mechanism broken away, and withcertain of the surrounding structure shown diagrammatically and insection.

FIGURE 2 is a vertical sectional view through the doorway, showing thedoor in its closed position in edge elevation, the viewpoint beingindicated by the line 2-2 of FIGURE 1, and showing the door in dot-dashlines in its open position.

FIGURES 3, 4, 5 and 6 are sequential views, as though in plan, lookingdownwardly at the top of the door, and with various parts broken away toshow the relationship of parts in the different successive positionsduring opening, from the closed position of FIGURE 3 to the openposition shown in FIGURE 6 in dot-dash lines.

Details of the aircraft cabin structure are immaterial, and no attempthas been made to show them herein, except as the structure, designatedgenerally by the numeral 9, has a doorway to the exterior defined by thesill 90, the lintel 91, and two spaced side jambs, designated, todistinguish them, by the numerals 92 and 93. These two jambs are shownas beveled, with their respective bevels converging outwardly so thatthe doorway, thus defined, is laterally of less width at the outersurface of the cabin than at the inner surface thereof. The sill andlintel, however, are uninterrupted and parallel.

A door 8, of a height just sufiiciently less than the spacing betweenthe sill 90 and the lintel 91 to pass therebetween, is of a width andshape complemental to the jambs 92 and 93, whereby, when the door isseated from the interior outwardly against the jarnbs, any cabinpressure superior to ambient pressure, acting over the entire interiorsurface of the door, will urge the door outwardly and hold it seatedagainst the jambs. Suitable sealing provisions would be employed at thejambs, and at the sill and lintel as well, but these have been omittedfor simplicity of illustration.

The closed position of the door is shown in FIGURE 1, and in full linesin FIGURE 2, and is shown also in FIGURE 3. FIGURE 6 shows the fullyopen position of the door in dot-dash lines, and the dot-dash lineshowing in FIGURE 2 also illustrates the door in its fully openposition. In such open position it is wholly exterior of the aircraftcabin, and alongside the doorway. Preferably its curvature, whichmatches the curvature of the cabin structure, is placed in generalparallelism with the cabin structure at the side of the doorway.Obviously the door cannot be moved directly outwardly from the closedposition of FIGURE 3 to the fully open position shown in dot-dash linesin FIGURE 6. According to the present invention, its movement betweensuch two terminal positions is accomplished by doorsupporting and-guiding mechanism, such as will now be described in detail.

The door is supported at top and bottom primarily by a pair of shortlever arms 1. These short lever arms are pivotally mounted at one endupon a rotative upright shaft 10, supported in brackets 95 which are ineffect part of the aircraft cabin structure, whereby the arms 1 mayswing from an inwardly inclined position, shown in FIGURE 3, wherein thedoor is fully closed, to an outwardly and oppositely inclined position,shown in FIGURE 6. The swinging end of each lever 1 carries a pivot pin11, by which the swinging end of each arm 1 is pivotally interconnectedwith one end of a long lever arm 2. The opposite end of this long leverarm 2 is pivotally connected to the door 8 at a pivot point 20 which islocated intermediate the side edges of the door, and preferablyapproximately midway therebetween. In addition, each pivot pin 11 isreceived, when the door is seated, within the inwardly opening slot 81of a bracket 80, which is fixed upon the door adjacent its one edge,that edge which is first to be projected outwardly through the doorwayin opening. So long as the pivot pin 11 remains engaged with its bracket80, the long lever arm 2 is motionless and ineffective with respect tothe door, and hence in effect the door is supported solely by the shortlever arms 1.

Since the short lever arms 1 in the closed position of the door,illustrated in FIGURE 3 are inclined inwardly,

it is evident that initiation of clockwise rotation of the short leverarm 1, engaged at its swinging end with the bracket 80, will displacethe door 8 bodily to the left, provided the doors second or left edge ispulled inwardly to clear the jamb 93. Mechanism to efiect such tiltingmovement of the door will now be described.

A long link 3, of which there need be only one, located adjacent thehead of the door, is pivotally connected at one end at 30 to the door 8,adjacent its second edge, and the other end of the link 3 is pivotallysupported at 31, although indirectly, from the cabin structure. Thepreferred connection is by means of a short link 32, pivotallyinterconnected at 31 to the longer link 3, and pivotally connected at 33to the cabin structure. A tie rod or link 4 interconnecting the pivot at31 with the pivot pin 11 completes the door-gliding mechanism.

The length of the link 4 is approximately the distance between thepivots 20 and 39 upon the door. The length of the long link 3 isapproximately the same as the length of the long lever arm 2. Theseelements, then, with the portion of the door intervening between thelinks 20 and 3t), constitute an articulated approximate parallellinkage. The short link 32 approximates the same length as the shortlever arm 1, and since the pivot 10 and the pivot 33 are relativelyfixed, both being at fixed points upon the cabin structure, and sincethe tie link 4 interconnects the pivots 11 and 31, these short armsconstitute in effect a part of an articulated quadrangular linkage, butwith parts so arranged that the lever arm 1 and the link 32 are seldom,in fact in only one position during their movement, in parallelism.

Clockwise rotation of the pivot shaft 10 may be effected by means of ahand lever 12, by the action of a member of the planes crew. Startingwith parts in the closed position of FIGURE 3, such rotation will actupon the door at the now fixed connection of the pivot pin at 11, tourge the door to the left, as well as moving its first edge outwardly.This motion of the pivot pin 11 is communicated through the tie link 4to the short link 32 and to the long link 3, and they will move into theposition shown in FIGURE 4, pulling the second edge of the doorinwardly, in order to permit the leftward movement of the door. InFIGURE 4 the connected ends of the lever arms 1 and 2 have been brokenaway, but the pivot pin 11 is shown in its still-connected relation tothe bracket 8 and its slot 81. The short lever arm 1 has moved from thedot-dash line position A of FIG- URE 4, which represents its position inFIGURE 3, to the position shown in full lines in FIGURE 4.

Coming to FIGURE 5, and continuing the clockwise rotation of the shortlever arm 1, the first edge of the door, that adjacent the jamb 92, isnow moving more rapidly outwardly through the doorway. The short leverarm 1 has moved from the dot-dash line position B of FIGURE 5, whichcorresponds to its position in FIGURE 4, to the position shown in fulllines in FIGURE 5. The door-guiding mechanism, including the links 3 and32, has further titled the doors second edge, that adjacent the jamb 93,further inwardly. 'Ihe pivot pin 11 is still engaged within the slot 81of the bracket 80.

Continuing clockwise rotation of the short lever arm 1 from its positionC, corresponding to the full-line position of FIGURE 5, eventuallybrings parts to the fullline position of FIGURE 6. By reason of therestraint on the pivot pin 11 afforded by the tie link 4 and thecontinued outward urging of the long link 3, the bracket has withdrawnfrom engagement with the pivot pin 11, the short lever arm 1 has reacheda terminal position, and yet for the time being the door is held in afixed position by the interconnected links and levers, that is, it maynot tilt about any single pivot axis. The pivots at 11 and at 31 beingnow fixed, it is clear that the long lever arm 2 and the long link 3 mayfunction thereafter as an approximate parallelogram, so that if the dooris grasped by the handle 20a it may be pushed outwardly, rotating, inthe manner shown in the dot-dash line arcs D of FIGURE 6, into the finalopen position, shown in that view in dot-dash lines.

In closing the door the above operations proceed in reverse. The door isswung about the pivots 11 and 31 until the bracket 80 reengages itsnotch 81 with the pivot pin 11, after which the shaft is rotatedcounterclockwise, and the door proceeds through the several positionsillustrated in reverse order, until it finally reaches the fully closedposition of FIGURE 3.

Weclaim as our invention:

1. In combination with the structure of a pressurized aircraft cabinwhich has a doorway to the exterior defined by a sill, a lintel, and twospaced jambs, a door of a height just sufiiciently less than the spacingbetween the sill and lintel to pass therebetween, and of a width exceeding the spacing between the jambs, whereby to be held seated fromthe interior upon said jambs by the cabin pressure, means pivotallyconnected to the door intermediate its sides, and pivotally connected toone side of the doorway, said means supporting and guiding the door fortranslational movement laterally of the doorway and for swingingmovement about said pivotal connections, and motion-controlling meansinterconnecting the door and the cabin structure, and coordinated withsaid supporting and guiding means to tilt the door about its pivotalconnection to said means, and to displace the door laterally relative tothe doorway, upon initiation of opening movement of the door, until oneupright edge of the door swings outwardly through the doorway, and itsother upright edge swings inwardly, said supporting and guiding meansand said motion-controlling means being further coordinated to displacethe so outwardly swung edge of the door beyond its jamb, to leave thedoor in its open position outside of the cabin structure and at one sideof the doorway.

2. In combination with the structure of a pressurized aircraft cabinwhich is formed with a doorway to the exterior defined by a sill, alintel, and two spaced jambs, a door of a height just sufficiently lessthan the spacing between the sill and the lintel to pass therebetween,and of a width exceeding the spacing between the jambs, whereby to beheld seated upon said jambs by the cabin pressure acting outwardly uponthe interior surface of the door, means defining a first pivot axis uponthe door located intermediate its upright side edges, elongatable andcontractible means pivotally supported upon the cabin structure at oneside of the doorway, and connected to the door at said pivot axis, forthe support of said door, means defining a second pivot axis upon thedoor, ofiset from said first pivot axis, and means operativelyinterconnecting the cabin structure and said second pivot axis, forcontrolling movement of the door as it swings with said door-supportingmeans, to tilt at first edge of the door outwardly about its first pivotaxis and through the doorway as its opposite edge tilts inwardly, andsimultaneously to displace the door laterally towards such oppositeedge, by elongation of said door-supporting means, in intiating openingmovement of the door, said doorsupporting and movement-controlling meansthereafter cooperating to guide the door outwardly through and reverselylaterally of the doorway, and through successive definite positions intofully open position, wherein the door is located outside of the cabinstructure and alongside the doorway.

3. In combination with the structure of a pressurized aircraft cabinwhich is formed with a doorway to the exterior defined by a sill, alintel, and two spaced jambs, a door of a height just sufficiently lessthan the spacing between the sill and the lintel to pass therebetween,and of a width exceeding the spacing between the jambs so as to be heldseated upon said jambs by the cabin pressure acting outwardly upon theinterior surface of the door, means defining a first upright pivot axisupon the door located approximately midway between its side edges, meansdefining a second pivot axis upon the door adjacent a first side edge, apair of vertically spaced short lever arms pivotally mounted coaxiallyupon the cabin structure adjacent such first side edge of the door, anddisconnectibly pivotally connected at their swinging ends to saiddoor-mounted means at the second pivot axis, and inclined inwardly ofthe cabin when the door is seated upon the jambs, a long door-supportingarm pivotally connected at one end to said short lever arm at a pointwhich is held by the latter coaxial with the doors second pivot axis solong as said short lever arm is connected to that second pivot axis,said long arm being connected at its other end to said first pivot axis,means defining a third pivot axis upon the door, adjacent its secondedge, being the edge which is opposite the location of the second pivotaxis, and means operatively connecting the cabin structure and the thirdpivot axis, for controlling movement of the door, in cooperation withsaid short and long arms, to shift the door laterally as the short armswings outwardly from its door-seated position, and simultaneously totilt the first edge of the door outwardly through the doorway and itssecond edge inwardly, and thereafter, upon disconnection of the shortarm from the second pivot means and continued outward swinging of saidshort arm, to guide the door through successive definite positions to afinal position without the cabin structure and alongside the first edgeof the doorway.

4. The combination of claim 3, wherein the door-controlling meansincludes a link pivotally connected to the door at the third pivot axis,and pivotally supported from the cabin structure in approximateparallelism with the long door-supporting arm.

5. The combination of claim 3, wherein the door-controlling meansincludes a first long link pivotally connected to the door at the thirdpivot axis, of a length approximating the length of the longdoor-supporting arm, a short link of a length approximating the lengthof the short lever arm, pivotally mounted at one end upon the cabinstructure intermediate the jambs, and pivotally supporting the longlinks other end, and second long link joining the pivotal joint betweenthe two lever arms with the pivotal joint between the first long linkand the short link.

6. In combination with the structure of a pressurized aircraft cabinwhich is formed with a doorway to the exterior defined by a sill, alintel, and two spaced jambs, a door of a height just sufficiently lessthan the spacing between the sill and the lintel to pass therebetween,and of a width exceeding the spacing between the jambs so as to be heldseated upon said jambs by the cabin pressure acting outwardly upon theinterior surface of the door, an inwardly opening slotted bracketmounted upon the door adjacent a first jamb, a long and a short leverarm and a pivot pin pivotally interconnecting said arms, said pivot pinbeing received in the bracket's slot while the 'door is held seated, theother end of the long arm being pivotally connected to the door,intermediate its side edges, and the short arm being pivotally supportedupon the cabin structure adjacent the first jamb, and inclined inwardlywhile the door is held seated, and door-controlling means in eluding along link pivotally connected at one end to the door adjacent the secondjamb, and pivotally supported at its other end from the cabin structure,and means to maintain the long link in general parallelism with the longlever arm, prior to and after disconnection of the bracket from itsengaged pivot pin, and during outward swinging of the short lever arm toproject the door edgewise outside the doorway, and then laterally to anopen position alongside the doorway.

7. The combination of claim 6, wherein the door-controlling means, andin particular its means to maintain parallelism, includes a second longlink pivotally joined at one end to the first long link at the lattersend distant from the door, and pivotally joined at its other end to thepivot pin which interconnects the long and short arms, and meanssupporting the common pivot connection between the two long links fordisplacement thereof, as the door moves towards its open position,outwardly and then towards the first jamb.

8. The combination of claim 7, wherein the means supporting the commonpivot of the two long links comprises a short link pivotally joined atone end to that common pivot, and pivotally supported at its other endupon the cabin structure, said short link being of a lengthapproximating the length of the short lever arm.

9. In combination with the structure of a pressurized aircraft cabinwhich is formed with a doorway to the exterior defined by a sill, alintel, and two spaced jambs, a door of a height just sufficiently lessthan the spacing between the sill and the lintel to pass therebetween,and of a width exceeding the spacing between the jambs so as to be heldseated upon said jambs by the cabin pressure acting outwardly upon theinterior surface of the door, supporting and guiding mechanism for thedoor comprising a long and a short arm pivotally interconnected and along and a short link pivotally interconnected, and laterally displacedrelative to the long and short arms, said arms and links being pivotallymounted, the shorter elements upon the cabin structure and the longerelements upon the door, a tie link joining the common pivot of the armsand the common pivot of the links to define a double quadrangle whereinthe longer elements are generally parallel in all their positions, andthe shorter elements are in most positions non-parallel, and arearranged to cooperatively effect lateral displacement and tilting of thedoor at one edge outwardly through the doorway in the initial stage ofits opening movement, and means releasably interengageable between thedoor, at one edge, and one such common ivot, releasable following suchinitial opening movement of the door to free the longer elements forconjoint pivotal movement relative to the shorter elements, to displacethe door laterally to one side of the doorway as continued movement ofthe shorter elements completes its projection outwardly of the doorway,

10. In combination with the structure of a pressurized aircraft cabinwhich is formed with a doorway to the exterior defined by a sill, alintel, and two spaced jambs, a door of a height approximating thespacing between the sill and lintel but sufiiciently less that it maypass therebetween, and of a width exceeding the spacing between jambs soas to be held seated upon said jambs by the cabin pressure actingoutwardly upon the interior surface of the door, and guiding andsupporting means interconnecting the door and the aircraft structureadjacent the doorway, organized and arranged to displace the door, inopening outwardly from its closed position, initially inwardly at afirst edge and bodily laterally with said first edge leading, andoutwardly at the second edge, and subsequently edgewise outwardlythrough the doorway with said second edge leading, to an opened positionsubstantially clear of the doorway and outwardly of the aircraftstructure.

11. In combination with a wall structure having a doorway defined by asill, a lintel and two spaced jambs, a door of a height justsufficiently less than the spacing between the sill and lintel to passtherebetween, and of a widih exceeding the spacing between the jambs,whereby the same is adapted to be seated from one side of said wallstructure upon said jambs, means pivotolly connected to the doorintermediate its sides, and pivotally connected to the wall structure atone side the doorway, said means supporting and guiding the door fortranslational movement laterally of the doorway and for swingingmovement about said pivotal connections, and motioncontrolling meansinterconnecting the door and the wall structure, and coordinated withsaid supporting and guiding means to tilt the door about its pivotalconnection to said means, and to displace the door laterally relative tothe doorway, upon initiation of opening movement of the door, until oneupright edge of the door swings through the doorway in the directionfrom the first-mentioned side of said wall structure toward the oppositeside thereof,

and its other upright edge swings oppositely, said supporting andguiding means and said motion-controlling means being furthercoordinated to displace the firstmenzioncd upright edge of the door soswung through the doorway, beyond its jamb, to leave the door in openposition at the second-mentioned side of the wall structure and atoneside of the doorway.

12. A safety closure for an outward opening in an air-pressurizedenclosure, comprising: a plug-type obturator having a face of an arealarger than the arm of the outer face of the opening in the closure;support and guide means pivotally connecting one edge of the obturatorto the adjacent edge of said opening, said support and guide means beinginterconnected for conjoint movement relative to the obturator; each ofsaid means being so shaped and arranged with reference to said enclosureand said obturalor as to displace the obturator inwardly upon manualoperation of the some, at a first edge; continued operation of theobturator moving same bodily laterally and inwardly with said first edgeleading, and inwardly overlapping the adjacent edge-region of saidenclosure and with the opposite, second edge displaced laterally fromits adjacent enclosure edge-region and toward said opening; theaforesaid shape and arrangement of said means constraining furthercontinued operation of said obturator to sidlc said obturator bodilyedgewise outwardly through said opening with the secand edge leading,and thence into final position clear of said opening, the first andsecond edges of said obturator being spaced apart .sufiiciently by thewidth of the obturator and being so formed along substantially theirfull length in relation to the corresponding edges of the closureopening as to overlap and rest against the latter edges alongsubstantially their full length, from the inside of said closure, withthe obturator in its closed position.

13. A closure arrangement for an outward opening in an enclosure, theperiphery of the opening being outwardly substantially wedge shaped,comprising: an obtumtor normally having an overall effective heightapproximating that of said opening and of an overall width exceedingthat of said opening, said obturator having a periphery formed with anoutwardly converging substantially wedge shape complementary to that ofsaid opening so as to enable said obfurator to be plugged outwardly intosaid opening; an obturator supporting and guiding means interconnectingthe obturator and the enclosure and initially rendered operative byinward unplugging of said obturator, said supporting and guiding meansbeing constructed and arranged with reference to the construction of theobturator and to that of the inwardly adjacent portion of the enclosureto constrain the obturator, upon inwardunplugging manual movementthereof, to be first displaced bodily laterally and inwardly at the oneedge of the obturator, the opposite edge of the obturator trailing; saidguiding and supporting interconnecting means being also constructed andarranged to thereafter, upon continued application of force to theoblurator, to constrain the opposite edge of the obturator to bedisplaced bodily outwardly through said opening, leading the first edge,whereafzer said means is efiectivc to constrain the obturator to swingbodily outwardly and then inwardly into juxtaposition with the exteriorside of said enclosure; whereby to prevent opening of said obturatorwhile there is a predetermined outward extraneous pressure differ entialon its inner face while permitting eventually its outward clearingsubstantially entirely out of said dooropening.

14. The combination with an obturator for an opening in a pressurizedenclosure which opening is generally smaller than the general face areaof the obturator of: a pair of vertically spaced hinge units, disposedalong one edge-region of said obturator, each unit comprising a hingemember pivoted at its one end to the adjacent jamb-region of theenclosure and pivoted at its opposite end to the obturator; andobturator motion-controlling means comprising a first link pivotallyassociated at its one end with said opposite end of said hinge memberand having an opposite pivotal end; a second link having its one endpivotally attached to said obturator and its opposite end pivotallyassociated with the pivotal end of said first link; and means carried bythe obturator for operating said hinge units so as to initially efiectdisplacement of the obturator inwardly and laterally from a first edgeof the opening, with the opposite edge of the obturator concurrentlytranslating outwardly of said opening; said hinge units andmotion-controlling means then constraining the obturator to sidle bodilyoutwardly of said enclosure through said opening with said opposite edgeleading, thereafter to enable disposition of said obturator in generalparallelism with said enclosure,

References Cited in the file of this patent or the origmal patent UNITEDSTATES PATENTS 2,161,323 Stephenson June 6, 1939 2,564,988 Muller Aug.21, 1951 2,763,900 McAfee et a1 Sept. 25, 1956

